/* px  em（受父容器影响） rem 等长度单位演示*/

html{
    font-size: 62.5%   /*16px*0.625=10px; */
}


body{
    font-size: 1em;
}

.value_px{
    font-size: 32px;
}

.value_em{
    font-size: 2em;
}


.value_rem{
    font-size: 2rem;
}

/* 颜色 */
.clss_name{
    color: red;
}

.class_hex{
    color: #00ff00;
}

.class_fun{
    color: rgb(0,0,255);
}



/*图片函数url*/
.img_url{
width: 262px;
height: 70px;
background-image: url(qq_logo.png);
font-size: bolder;
}


/*常见字体样式属性*/
.font_demo{
    /* font:400; */
    color: red;
    font-family: "微软雅黑",  sans-serif,;
    font-size: 2em;
    font-style: italic;
    font-weight: normal;
}


/* 常见文本样式属性 */
.text_demo{
font-size: 2em;
border: 1px solid black;
width: 50rem;
height: 10rem;
text-align: center;
line-height: 100px;
text-decoration: underline;
text-indent: 3rem;
letter-spacing: 1rem;
word-spacing: 2rem;
}


/* 列表样式属性 */
ul{
    font-size: 2rem;
}

.list_demo1{
  list-style: circle inside;
}

.list_demo2{
    list-style: none;
}

.list_demo3{
    list-style-image: url(qq_logo.png);
    list-style-type: none;
    list-style-position: inside;
}

.list_demo4{
    list-style: none url(la.jpg) inside;
}

/* 背景样式属性 */
.bg_box{
    border: 1px solid red;
    width: 40rem;
    height: 20rem;  
}
.bg_demo1{
 background-color: coral;
}

.bg_demo2{
    background-image: url(qq_logo.png);
}
.bg_demo3{
    background-image: url(qq_logo.png);
 /* background-repeat: no-repeat; */
    background-repeat: repeat-y;
}
.bg_demo4{
    background-image: url(qq_logo.png);
    background-repeat: no-repeat;
    background-position: center center ;
}
.bg_demo5{
    background-image: url(qq_logo.png);
    background-repeat: no-repeat;
    background-position: top right;
    background-attachment: scroll;
}
.bg_demo6{
    background: #15ff00 url(qq_logo.png) no-repeat top right fixed;
}


/* 表格样式 */
.table_demo{
    font-size: 3rem;
    border: 1px solid #000;
    width: 70%;
    margin: 0 auto ;
    table-layout: fixed;
    border-collapse: collapse;
    border-spacing: 10px;
    caption-side: top;
}
.table_demo caption{
    font-size: 2.5rem;
}

.table_demo th,  .table_demo td{
    border-top: 1px solid #000;
    border-bottom: 1px solid #000;
    text-align: center;

}
.table_demo thead{
    background-color:red;
    color: white;
}
.table_demo tbody tr :hover{
    background: yellow;
    cursor: pointer;
}
.table_demo tfoot td{
    text-align: right;
    padding-right: 2rem;
}

/* 表单样式 */
.form_demo{
    font-size: 1.4rem;
    border: 1px solid seagreen;
    background: #fff;
    width: 35rem;
    height: 25rem;
    text-align: center;
}
.form_demo input[type="text"],.form_demo input[type="password"]{
    border-right: 0;
    border-right: 0;
    border-top: 0;
    border-bottom: 1px solid #000;
     height: 42px;
     width: 200px;
     padding: 47px;
}

.form_demo #username{
    background: #fff url(username.png) no-repeat top left;

}

.form_demo #pwd{
    background: #fff url(password.png) no-repeat top left;
}

.form_dome [type="submit"]{
    width: 100px;
    height:38px ;
    background-color: rgb(233,85,85);
    border: 1px solid #2e5bec;
    border-radius: 10px;
}